Evaluation of protection and acquired immune response elicited by inoculation with vNA-Δ.

<p>C57BL/6 mice were inoculated with PBS (mock) or infected intranasally with 10⁵ PFU Influenza A/PR8 virus, 10³ or 10⁵ PFU of vNA-Δ virus. Twenty-one days after the prime-inoculation the animals were challenged with a lethal dose of 10⁵ PFU of PR8. The weight loss and survival were determined after the prime-inoculation (A) and the challenge (B) infection (data represents two independent experiments). Blood and BALF were collected fourteen days after prime-inoculation and challenge infections. Tenfold dilutions of BALF samples were used to determine total IgG (C) and IgA (D) in BALF and total IgG in serum by ELISA (E)(Data depict one representative experiment). Two fold serial dilution of serum was used for the hemagglutinin-inhibition assay (F). n = 4 for BALF IgA and IgG measures after inoculation. n = 4, 7, 7, 6 for mock, vNA-Δ 10³, vNA-Δ 10⁵, PR8 10³ for serum IgG. n = 4, 5, 6, 5 for mock, vNA-Δ 10³, vNA-Δ 10⁵, PR8 10³ for hemagglutinin-inhibition assay (Data represents two independent experiments). Spleens of mice (n = 4) were obtained two weeks after the inoculation or challenge infection. Specific NP CD8+ T cells were assessed by ELISPOT using nucleoprotein (NP) of PR8 ASNENMETM peptide (NP; aa 366–374) as stimulus (G) Data represents two (inoculum) or three (challenge) independent experiments. Data were evaluated by Mann-Whitney test *, ** and *** for p<0.05, p<0.01 and p<0.001 respectively.